One vertex per element, one color per generator, with an edge from x to x·s.
(2,4)(7,11)(10,12)(13,14,16,21,17,19,23,18)(15,20,22,27,24,26,28,25)(6,9)(7,11)(14,18)(15,22)(16,23)(19,21)(24,28)(25,27) involution — undirected(1,2,3,4)(5,6)(7,10)(8,9)(11,12)(14,19)(18,21)(20,26)(25,27)(6,9)(10,12)(13,15,23,28,17,24,16,22)(14,20,18,25,19,26,21,27)(5,7,8,11)(6,10,9,12)(15,24)(20,26)(22,28)(25,27)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.